title: Biotransformation of the UV-filter sulisobenzone: challenges for the identification of transformation products.
abstract: The UV-filter substance Sulisobenzone (BP-4) is widely employed in sunscreens and other personal care products. In the current study, its behavior during biological wastewater treatment was investigated. In contact with activated sludge BP-4 was degraded in aerobic batch experiments forming at least nine transformation products (TPs). The mass balance in the batch experiments was closed, as measurements with LC-UV underlined that the quantity of the TPs was comparable to the BP-4 quantity transformed. The chemical structures of the nine TPs could be proposed based on accurate mass measurements by high resolution mass spectrometry (LTQ-Orbitrap-MS), several fragmentation experiments up to MS(6) and synthesis of one TP. NMR analyses of the main TP confirmed its proposed chemical structure. At the beginning of the biotransformation of BP-4, a benzhydrol analogue was formed due to the reduction of the keto moiety. Further reactions (e.g., oxidation, demethylation, decarboxylation) led to the formation of extremely polar TPs. A biodegradation pathway was proposed based on the TP structures identified and the sequence of the TP formation. The isolated TPs exhibited higher toxic effects on Vibrio fischeri than BP-4. The results contribute to a better general understanding and prediction of the biotransformation of aromatic sulfonic acids in WWTPs.
authors.affiliation: Federal Institute of Hydrology (BfG), Am Mainzer Tor 1, 56068 Koblenz, Germany.
authors.forename: Rita
authors.initials: R
authors.lastname: Beel
authors.forename: Christian
authors.initials: C
authors.lastname: Lütke Eversloh
authors.forename: Thomas A
authors.initials: TA
authors.lastname: Ternes
mesh_terms: D000332:Aerobiosis; D048908:Aliivibrio fischeri / Q000187:drug effects / Q000378:metabolism; D001419:Bacteria / Q000378:metabolism; D001577:Benzophenones / Q000378:metabolism* / Q000633:toxicity; D001711:Biotransformation; D012722:Sewage / Q000382:microbiology; D013473:Sunscreening Agents / Q000378:metabolism* / Q000633:toxicity; D014865:Waste Disposal, Fluid; D014874:Water Pollutants, Chemical / Q000378:metabolism* / Q000633:toxicity
chemical_list: D001577:Benzophenones; D012722:Sewage; D013473:Sunscreening Agents; D014874:Water Pollutants, Chemical; C009361:sulisobenzone